Driving mechanism



Juy S? 1943. R R JACCARD 2,324,163

DRIVING MECHANISM Filed April 2, 1941 3 Sheets-Sheet 1 @ijf JUY 13 1943- P. R. JACCARD DRIVING MECHANSM Filed April 2, 1941 5 Sheets-Sheet 2 July 13, 1943- P. R. .JACCARD DRIVING MECHANISM Filed April 2, 1941 3 Sheets-Sheet 3 jz vena?? Ma /Zmw Patented July 13, 1943 DRIVING MECHANISM Philippe Ren Jaccard, Petit Lancy, Geneva, Switzerland Application April 2, 1941, Serial No. 386,557 In Switzerland April 1, 1940 6 Claims. (Cl. 185-40) This invention relates to driving mechanism of the type including an auxiliary spring for transmitting the driving torque with a constant force to the driven element.

Driving mechanisms of this type are used for example in clock movements having a powerful main spring which ensures a long running period, in order to avoid the disadvantageous ee-ct of the variation of the driving force of the unwinding spring on the running precision of the movement.

vKnown devices of this kind are of complicated and unreliable construction and can be used only in combination with clock movements of considerable size. It is an object of the present invention to provide a driving mechanism having an auxiliary spring, of the type referred to, which may be used also for small clock movements, for example in combination with pocket watch movements and chronometer movements, or also for speed indicators of vehicles. For marine and aviation chronometers it is particularly important that the movements have a long running period and are of highest precision.

Further objects and advantages of this invention will become apparent from the following detailed description of the invention, reference being had to the accompanying drawings showing several embodiments of the invention. In these drawings,

Fig. l is an elevation of a driving mechanism according to the invention, partially drawn in section.

Fig. 2 is a top plan view of the mechanism also partially shown in section.

Fig. 3 is an elevation of a modified mechanism.

Fig. 4 is a plan view of this modication.

Fig. is a section along the line V-V of Fig. 3.

Figs. 6, 'l and 8 show each a further modiiication of a driving mechanism according to the invention.

Figs. 9 to 12 show various modifications of details of the mechanism.

Figs. 13 and 14 show further details of the mechanism.

rThe mechanism represented in Figs. 1 and 2 can be combined with any existing watch or clock movement for example with a pocket watch movement or with a chronometer movement. I and 2 indicate the movement plates or bridges of the movement. 3 is a wheel which is connected to the barrel of the main spring, not represented, and which meshes with a pinion 4 carried on an arbor 5 which is mounted in bearings 6 and I of the plates I and 2. A gear wheel 8 is loosely carried on the arbor 5 and meshes with a pinion 9 of a wheel I0 which is connected to the usual escape wheel I0 forming a part of an oscillatory regulating device of the Watch movement. Accordingly the wheel 3 represents the center wheel, the wheel 8 the intermediate wheel and the wheel I0 the seconds wheel of the watch movement. Riveted to the pinion 4 or to the arbor 5 is a plate II which forms together with connecting pillars I2, I2 and a plate I3 of equal size a rotatable support. The pillars I2, I2 penetrate between the spokes I4 of the wheel 8.

A sleeve I5 is secured to the plate 2 and its upper portion penetrates through an opening in the lower plate I3 of the rotatable support. This sleeve carries a stationary gear I6 meshing with a pinion I'I of a wheel I3 which is rotatably carried between the two plates II and i3. This wheel I8 meshes with a wheel i9 of a similarly mounted wheel 20 and this latter in turn meshes with a pinion 2| of a braking disc 22 which is also carried between the two plates I I and I3 and situated in the plane of the loose wheel 8. When the support formed by the plates II and I3 and the pillars I2, I2 rotates owing to the driving action of the main spring connected to the wheel 3, the epicyclic gear train I'I, I8, I9, 28, 2I carried by this support also starts to rotate, since the stationary gear I6 imparts a movement of rotation to the pinion II rolling around the periphery of the gear I6. Accordingly, the braking disc 22 is caused to rotate With a great multiplication of speed by the epicyclic train. The number of planetary wheels could obviously be greater or smaller than represented by way of example. An auxiliary spring 24 is secured by a screw 23 to one of the spokes I4 of the loose wheel B and abuts against the pillar I2 connecting the plates II and I3.

It is understood that the auxiliary spring 24 is inserted between two relatively rotatable portions of the mechanism, one of these portions consisting o1" the wheel 3, the pinion 4, the support II, I2, l2', I3 and of the epicyclic gear train II, I8, I9, 20, 2I and 22 mounted on the support. This portion is placed under the action of the main spring. The other portion is responsive to the action of the auxiliary spring and comprises the wheel 8, the pinion 9, the wheels Il and including the regulating device. The braking disc 22, the wheel 8 and the pillar I2 are relatively positioned in such manner that a spoke I4 passes between the pillar I2 and the braking disc 22 and that only a very small play is present between the periphery of the braking disc 22 and this spoke, when the pillar I2 makes contact with the latter at the point 25. Though the wheel 8 is loosely mounted on the arbor 5, it can thus rotate only through a very small angle relatively to the support Ii, I2, l2', I3.

In position of rest of the movement and when the main spring is not tensioned, the auxiliary spring 24 which possesses a certain preliminary tension, acts on one of the spokes of the wheel 8; this wheel, however, cannot turn-since the spoke I4 passing between the braking disc 22 and the pillar I2 abuts against this pillar. When the main spring is wound up it imparts a movement of rotation to the support II, I2, l2', I3 in the direction of the arrow indicated in Fig. 2, by the intermediary of the wheel 3 and the pinion 4. The pillar I2 of the support then acts on the auxiliary spring 24 and tensions this spring, so that the wheel 8 starts to rotate under the action of the auxiliary spring and drives the escapement wheel by the intermediary of the pinion 9 and the wheel I8. During rotation of the support the pinion Il moves around the fixed gear I6 and tends to impart a rapid movement of rotation to the braking disc 22 by the intermediary of the train of wheels I8, i9, 20, 2I.

The wheel 8 connected to the escapement is now obliged to take part at theintermittent movement of the escapement and it turns and stop-s alternately according to the cadence of the regulating device. During the short stopping period of the escapement and of the Wheel 8, the support II, I2, I2', i3, however, continues its movement of rotation, as the action or the main spring is continuously eective. The pillar I2 accordingly moves away from the spoke I4 and simultaneously increases the tension of the auxiliary spring 24, but the braking disc 22 soon arrives in rcontact with the spoke. Owing to the great multiplication with which the braking disc is driven, this latter stops immediately after making contact with the spoke, independently of the force of the main spring. The disc 22 being stopped also causes the stopping of the epicyclic gear train and the pinion II can no more roll along the gear iii, so that the plates II and I3 are also obliged to stop and the pillar I2 does not act any longer on the auxiliary spring 24. As soon as the escapement eiects a new oscillation, the wheel 8 is allowed to continue again its rotation under the action of the auxiliary spring and the spoke Ill moves away from the braking disc 22 so that the `epicyclic gear train and accordingly the support I I, I2, I2', I3 can rotate again. At the next stop of the escapement the same operations are repeated.

It is seen that the braking disc 22 continuously follows the spoke I4 of the wheel 8; contact with the spoke and disengagement of the braking disc alternate according to the cadence of the escapement vas long as the main spring is suiciently wound up to cause the tension yof the auxiliary spring by rotation of the support II, I2, I2, I3. When finally the force of the main spring is not sufficient to overcome the force of the auxiliary spring, the braking disc does not arrive any more in contact with the spoke I4 and the pillar I2 slowly approaches the spoke until it makes Contact with this latter at 'the point 25. From this moment the movement does not operate with constant force and the escapement is only influenced by the main spring; in this condition, however, the movement soon comes to a standstill since the main spring has run down.

Practically, the play of the spoke I4 between the braking disc 22 and the pillar I2 measures only a few one hundredths of one millimeter. The tension of the auxiliary spring does practically not vary, and the force acting on the escapement is substantially constant independently of the degree of tension of the main spring.

The use of the pillar I2 acting as abutment for the spoke of the wheel 8 in close proximity to the spoke is not obligatory. In case the described mechanism replaces the center wheel, the intermediate wheel or the seconds wheel of a clock or watch movement, and when the almost run down main spring is not capable to tension the auxiliary spring any longer the abutment constituted by the pillar I2 acts to prevent the hands of the clock from stopping for a short period in the interval during which the wheel 8, rotating relatively to the support, moves from the position where it makes contact with the braking disc until it abuts against this pillar. But when the mechanism according to this invention is placed between the barrel of the main spring and the center wheel, the abutment at 25 is not required, since the hands are then connected to the train of wheels driven by the loose wheel 8.

As already specified, the diameter of the wheel 8 and accordingly the diameter of the mechanism as a whole for producing the constant torque is not greater than the diameter of the wheel of the clock movement which is replaced by this mechanism, and the existing gearing ratio between the barrel of the main spring and the escapement is not modied by this mechanism. The mechanism only comprises rotatable parts but no levers or cams. Since the braking disc 22 is situated in the plane of the loose wheel 8., any jamming of the wheels and pinions is avoided. The transmission device interposed between the driving wheel 3 and the driven pinion 9 and constituted by the arbor 5 with the pinion 4 and the wheel 8, the supporting member Il, I2, I2', I3, the epicyclic-train and the braking disc, forms a unit which can be installed as a whole in a clock or watch movement or any other movement requiring a constant torque driving force.

The modication represented in Figures 3, 4 and 5 is similar to the one just described with the exception that the auxiliary spring 24 is formed by a blade spring or a resilient thin -arm of the loose wheel 8, this arm extending from the hub of the wheel to not quite the rim thereof. The wheel 3 is again connected to the barrel of the main spring and meshes with the pinion 4 to drive the arbor 5 carrying the support II, I2, I3. The braking disc 22 is also situated in the plane of the wheel 8 and is driven by the epicyclic gear train Il, I8, I9, 20, 2l which is driven owing to rolling of the pinion Il along the xed gear I6. The loose wheel 8 meshes with the pinion 9 connected with the escapement as in the previous example.

rlhe operation of this mechanism is the same as that above described. When the support II, I 2, I3 rotates under the action of the 'main spring, the pillar I2 acts against the auxiliary spring 24 and this latter drives the wheel 3 and accordingly the escapement. When the escapement stops the support II, I2, I 3 continues its rotation and the braking disc 22 makes contact with the abutment 2G of the spoke I 4 of the wheel 8. The braking disc stops and prevents thus the further rotation of the support until the escapement, effecting its next oscillation, allows the continuation of the rotation of the wheel 8 "o'wing to the action of the auxiliary spring and the abutment 26 disengages the braking disc.

Instead of being connected to an escapement, the loose wheel 8 could be connected to a regulating device which is in continuous motion or even with a simple fly wheel which could be formed for example by the wheel 8 itself. In this case the wheel 8 would not effect an intermittent movement but would continuously move, but the operation of the mechanism would be the same, contact between the abutment of the loose wheel and the braking disc being obtained because the support carrying the disc tends to move faster than the loose wheel the movement oi which is controlled by the regulating device.

In the example according to Fig. 6 the braking disc 22 is not situated in the plane of the loose Wheel 8 but above this plane. .The plate I3 of the support of the epicyclic geartrain carries an arm 2'I to which is hinged a braking lever '28' cooperating with the braking disc 22. The arm 2'! also carries a bell crank lever 29 one end of which cooperates with a pin 38 fixed on the wheel 8 while its other end acts against the lever 28. A spring 3| tends to apply the lever against the braking disc. The auxiliary Spring 24 is formed as helical spring one end of which is xed to the wheel 8 and the other end to a tensioning arm 32 which is rotatably carried at 33 on the plate I3 of the support. The inner end of this tensioning arm is provided with a toothed segment 34 meshing with a rotatable toothed sleeve 35. Rotation of this regulating sleeve by hand produces a corresponding movement of the arm 32 and accordingly an increase or a decrease of the preliminary tension of the auxiliary spring 24 which can be adapted in this manner to the resistance to be overcome.

In the position represented in Fig. 6 the lever 28 makes contact with the braking disc 22and accordingly the epicyclic gear train and the plate I3 do not move. The loose wheel 3 rotates owing to the action of the auxiliary spring 24 so that the pin 30 acting against the bell crank lever 29 moves this lever which lifts the braking lever 28 off the disc 22. The plate I3 can continue to turn and as soon as the wheel 8 stops at the end of an oscillation of the escapement, the bell crank lever 29, continuing its rotation with the plate I3, moves awai7 from the pin 30, so that the lever 28 is again applied against the braking disc 22 by the action of the spring 3 I.

In the example according to Fig. 7 the epicyclic gear train I'I, I8, i9, 26, 2l driving the braking disc 22 is disposed as in Fig. 2 or 4. The auxiliary spring 24 is fixed with one of its ends on the loose wheel 8 and with the other end on one arm of a lever 3G rotatably carried at 3l on the plate II of the support of the epicyclic gear train. The other arm of the lever 36 cooperates with a cam 33 carried by the axis of the wheel 28 of the epicyclic gear train. This cam turning with the wheel produces a periodical oscillation of the lever 36 so as to effect a periodical variation of the tension of the auxiliary spring.

In the example according to Fig. 8 a portion of the epicyclic gear train driving the braking disc 22 is not mounted between the plates II, I3,

-but between the plate II and the loose wheel 8. The journals of the wheel 28 and of the braking disc 22 are inserted with a small play in their respective bearings 39 and 48. At the moment when the wheel 8 is stopped by the escapement while the plates II, I3 continue to rotate under the action of the main spring and must in turn be stopped, the axes of the wheel 28 and of the braking disc 22, owing to relative movement of rotation between the Wheel 8 and the plate II are brought unto an inclined position as indicated in dotted lines in Fig. 8, so that the rim of the braking disc 22 arrives in contact with the plate II whereby the braking disc is stopped and the further rotation of the plates II and I3 is prevented. Instead of disposing the braking disc 22 in proximity to the plate II, the disc could also be placed in proximity of wheel 8 so as to make contact with this wheel 8 in its inclined position and to prevent movement of the portion of the mechanism which is driven by the main spring.

It is possible to mount the sleeve I5 represented in Figs. l, 3 and 7 and carrying the iixed gear I6 in such marmer on the movement frame that it can move relatively to the frame. By rendering this sleeve loose it is possible to render the mechanisrn for producing the constant torque inactive, since the gear Iii can turn about its axis; the epicyclic gear train accordingly would not rotate and the support I I, i3 would transmit the driving force of the main spring immediately on the wheel 8 connected to the escapement.

Figs. 9 and l0 show two modifications of the manner in which the surplus driving force is loraked. The supporting plate I6 driven by the main spring as in the other examples rotatably carries at a braking lever i2 the free end of which loosely engages a pin i3 on the loose wheel 8. rIhe auxiliary spring 2da is inserted between the plate i3 andthe wheel 8. The braking disc 22 is driven as in the previous examples by the not represented epicyclic gear train. When the wheel 8 stops and the plate I3 continues to rotate, the lever i2 turns about the point t3; the braking disc 22 still. turning with the plate I3, arrives in contact with the lever and the plate I3 driven by the main spring also stops. Owing to the relative position of the braking disc 22 and the lever I2 which turns at the moment of braking about the pin d3, the eiect of the braking disc acting on the smaller lever arm is decreased. The braking disc could also act in proximity to the point il on the lever i2 whereby the braking action would be increased.

In Fig. l0 the braking lever d2 is rotatably carried at it on the loose wheel S and is guided by the pin di on the plate I3.

While in Figs. 9 and l0 the loose wheel 3 and the braking disc 22 are situated in approximately the same plane, they are disposed in dierent planes according to the examples oi Figs. 1l and l2. The auxiliary spring 2da is inserted between the plate I3 and a lever I4 extending substantially at right angles to the plates II and I3 and abutting against a spoke iii of the loose wheel. In Fig. ll the lever MI is mounted on the plate II and the braking disc 22 abuts against the free end of the lever. In Fig. l2 the lever 4G is rotatably mounted on the plate i3 and the braking disc 22 abuts against this lever in proximity to its point of rotation. The operation of these devices is otherwisethe same as in the examples above described.

In the examples of the invention described until now the wheel 8 connected to the escapement has been loosely mounted on the axis of rotation of the support II, I2 of the epicyclic gear train. As this wheel 8 practically effects only an extremely small rotation relative to the support, it is not absolutely necessary that the wheel is loosely mounted. In Fig. 13 a wheel 8 is rep-resented which is connected to the escapement and which comprises a hub 45 rigidly connected to the arbor 5. The spokes 24h of the Wheel are resilient and are yielding to permit the necessary small relative rotation of the rim of the wneel with `respect to the hub d fixed on the arbor 5. These spokes 2% can constitute at the `same time the auxiliary spring of the mechanism in which case the support of the epicyclic gear train driven by the main spring is directly connected to the ri-m of the wheel 8 and the spokes Zlib are continuously tensioned.

According to Fig. 14, the hub 136 of the wheel 8" is also rigidly connected to the arbor 5 of the support. The relative rotation of the Wheel with respect to the support is enabled by Spokes I4 which are hingedly connected with the hub and with the rim of the wheel. This construction 'of the wheel 8 connected to the escapement offers the advantage that the frictionai forces acting on this wheel are reduced to a minimum; this device is accordingly particularly useful in laboratory movements which require highest precision.

Although I have Shown and described preferred embodiments of my improved driving mechanism as applied to watches and clocks, I do not desire my invention to be limited to the particular use and arrangements disclosed, as there may be changes made in the arrangement, description and forni of the parts without departing from the scope of the appended claims.

I claim:

1. A driving mechanism for"transmitting the :driving force with constant torque from a driving member to a speed controlled driven member, said mechanism including a transmission unit adapted to be installed as a unit between the driving and driven members, said unit including a rotatable arbor adapted to be connected to the driving member, a supporting member mounted for rotation with said arbor, a wheel loosely carried by said arbor and adapted to be connected to said driven member, an auxiliary driving spring interposed between the supporting member and said wheel, a stationary gear mounted coaxially with said arbor, a braking disc carried by the supporting member, a planetary gear carried by the supporting member and meshing with said stationary gear, a wheel train operatively connecting the planetary gear to said braking disc to impart rotation of the disc upon rotation of the supporting member, and means coacting with the braking disc for frictionally engaging the disc to prevent substantial relative movement between the supporting member and said loose Wheel and to maintain said auxiliary spring at substantially uniform tension.

2. In a driving mechanism, the combination with a rotatable driven arbor, of a wheel coaxially mounted with said arbo-r for rotation relatively lating means operatively connected to said coaxially mounted wheel to control rotation of said wheel, and means effective upon an increase of speed of said supporting member relatively to said coaxially mounted wheel for irictionally engaging said braking disc and preventing rotation of the planetary gear and the supporting member.

3. In a driving mechanism comprising a gear train for transmitting driving motion between driving and driven members, said gear train including a rotatable arbor connected to the driving member, a wheel coaxially mounted with said arbor for rotation relativelythereto, a supporting member rotating with said arbor, spring means interposed between the supporting member and said coaxially mounted Wheel to transmit movement from said arbor to said wheel, a braking disc eccentrically mounted on said supporting member, a xed gear coaxial with said arbor, a planetary gear rotatably carried by the supporting memberand interposed between the xed gear and said braking disc to impart rotary movement to the disc upon rotation of the supporting member, a movement regulating means operatively connected to said coaxially mounted wheel to control the rotary movement of the wheel, and means on said coaxially mounted wheel for frictionally engaging said braking disc upon an increase of speed of said supporting member relatively to said Wheel to prevent rotation of the planetary gear and thereby stop the supporting member.

4. In a timepiece having a winding motor, an escapement device and a gear train for transmitting movement from the winding motor to the excapement device, said gear train including la rotatable arbor, a supporting member mounted on said arbor for rotation therewith, a wheel loosely mounted on the arbor, a spring interposed between said supporting member and said loosely mounted wheel to transmit rotary movement from said arbor to the wheel, said wheel being con.- nected to the escapement device whereby the wheel is compelled to intermittently turn in 'accordance with the cadence of the escapement device, a rotatable friction disc mounted on said supporting member and situated in the plane of said loosely mounted wheel, a stationary gear mounted coaxially with said arbor, a planetary gear train mounted on said supporting member and interposed between the stationary gear and the braking disc to impart rotary movement at relatively high rate of speed to the disc upon rotation of the supporting member, means on said wheel for frictionally engaging said disc when the wheel is stopped by the action of the escapement device and said supporting member moves relativeiy to the wheel, to thereby stop said braking disc and prevent further movement of the supporting member until the escapement device releases Vsaid loosely mounted wheel.

5. In a driving mechanism having a driving `motor and an auxiliary driving spring for transmitting a constant torque to the driven member, -a gear train for transmitting movement between driving and driven members, said gear train including `a rotatable arbor connected to the driving motor, a supporting member mounted for movement with said arbor, a spoked Wheel loosely mounted on the arbor, said auxiliary driving spring being interposed between said supporting member and wheel to transmit movement from lsaid arbor to said wheel, an esc'apement device operatively connected to said loosely mounted wheel whereby said wheel is compelled to intermittently turn in accordance with the cadence of the escapement device, a rotatable braking disc mounted on said supporting member, a stationary gear mounted coaxially with said arbor, a planetary gear train mounted on said supporting member and interposed between said stationary gear and the braking disc to impart rotary movement to said braking disc upon rotation of thesupporting member, the braking disc having its periphery in close proximity to one of the spokes of said loosely mounted wheel, whereby said spoke is adapted to frictionally engage the braking disc when the loosely mounted wheel is stopped by the action of the escapement device and the supporting member moves relatively to the wheel while tensioning said auxiliary driving spring, to thereby stop said braking disc and planetary gear train and prevent further movement of the supporting member until the escapement device releases said loosely mounted wheel.

6. In `a driving mechanism having a gear train for transmitting driving motion between driving and driven members, said gear train including a rotatable arbor connected to the driving member, a wheel coaxially mounted with said arbor for rotation relatively thereto, spring means interposed between said arbor and said wheel to transmit driving force from said arbor to said wheel, an escapement device operatively connected to said wheel whereby the wheel is compelled to intermittently turn and stop in accordance with the cadence of the escapement device to produce energization of said spring means upon movement of said arbor relatively to said wheel, and a braking device responsive to such relative movement between the arbor and the wheel for stopping the arbor to prevent further energization of the spring means and releasing the arbor upon said escapement device allows the wheel to continue its rotation.

PHILIPPE RENE JACCARD. 

